In the fabrication of high-pressure cylindrical vessels for use as storage tanks, reactors and the like, care is taken to provide shrinkage designed to produce an internal strain or pressure adapted to take up at least some of the pressure developed by a fluid within the vessel. The thickness of the vessel is dimensioned to bring about the desired strain or internal prestress so that, when the vessel is loaded, the outward forces are balanced by the prestress.
In determining the thickness of the vessel, the degree of prestress brought about by the manufacturing process must be established for various thicknesses and it has been the practice heretofore to evaluate the shrinkage effect by forming test samples and applying destructive or distortive testing techniques to determine the yielding and rupture characteristics of the samples. Models of the vessel may also be required for these conventional processes.
The prior-art techniques thus have the disadvantage that considerable time may be required for fabricating the test samples and providing the knowledge gained by testing them in the fabrication of full-scale vessels to be subjected to high pressures.